Imperative programming is characterized by explicit 'flow control' using for loops (for iteration) and if statements (for conditionals) as foundin familiar scripting and programming languages such as Python. Imperative programming is useful to perform iteration, either steppingthrough a collection or to perform some iterative feedback or optimisation loop.

Associative programming uses the concept of graph dependencies to establish 'flow control’ and is useful for modeling complex operations(such as geometric processes) applied to collection of objects, in a very succinct programming style with automatic change propagation.

The two styles of programming address different computational tasks and essentially complement each other. The different styles ofprogramming share a common notation which means that in some case the same code can be executed either associatively or imperatively. Inaddition there are certain computational tasks that benefit from a combination of programming styles within the same program or indeedwithin the same function or method. DesignScript supports this flexibility by allowing Imperative code to be nested within Associative codeand vice versa.